1. Field
Apparatuses and methods consistent with example embodiments relate to an electronic circuit, and more particularly, to an asynchronous successive approximation register (SAR) analog-to-digital converter (ADC) and a semiconductor device including the same.
2. Description of the Related Art
An ADC is a device that converts an analog signal into a digital signal. A SAR ADC includes a SAR and compares a digital code including a plurality of bits with an analog signal while sequentially increasing or decreasing the digital code starting from an upper bit to approximate the digital signal to the analog signal. An asynchronous SAR ADC operates according to an internal operating clock signal generated in an ADC based on an externally input sampling clock signal, and is different from a synchronous SAR ADC receiving an externally input operating clock signal.
Because an asynchronous SAR ADC uses an internal clock signal, metastability may occur when a reference voltage is compared with an input voltage in a comparator. When a ring oscillator is designed to overcome the metastability of the asynchronous SAR ADC, an operating frequency may increase or decrease due to process, voltage and temperature (PVT), which deteriorates linearity.